Title: When Meteorology Meets Oceanography at Mesoscales: Vortex Rossby Waves and Curved Frontal Jets
Abstract:
Building on classical theories in dynamical meteorology, I present two examples at ocean (sub)mesoscales: vortex Rossby waves (VRWs) and curved frontal jets. First, I show how VRW theory, developed to explain spiral rainbands in tropical cyclones, illuminates the structure and evolution of ocean mesoscale eddies (~100 km). Whereas planetary Rossby waves are supported by the meridional gradient of planetary potential vorticity (PV), VRWs propagate on the radial PV gradient of a vortex. Using dispersion relations derived from the quasigeostrophic (QG) PV equation, I contrast sheared VRWs in tropical cyclones with discrete VRWs in ocean eddies. Second, motivated by precipitation patterns associated with upper-level atmospheric jets, I examine vertical motion at curved ocean fronts. Classical frontogenesis theory diagnoses vertical motion through Q-vector forcing in the omega equation, with shearwise Q-vector dominating over transverse Q-vector at curved fronts. By expressing the QG momentum equations in front-following coordinates, I offer a complementary perspective that isolates the role of front curvature in driving along-front ageostrophic flow and the resulting vertical motion. This framework provides a simple diagnostic of ageostrophic motions based on satellite sea surface height.
